Eyes of Battle (Su)
Source: Advanced Class Guide, p. 38
The shaman’s senses become magically heightened in the heat of battle. As a swift action, she can grant herself a +10 insight bonus for 1 round on Perception checks made to notice and pinpoint invisible creatures within 30 feet. She can instead use this ability as a swift action to ignore the effects of cover or partial cover (but not total cover) on her next attack, as long as that attack is made before the end of her next turn. The shaman can use this ability a number of times per day equal to her shaman level.